This invention concerns a cutting device for folded and unfolded sheets, as well as booklets, with at least one rotating cutting knife and one conveyer which transports the material to be cut at least during the cutting process. The device also has at least one endless conveyer element which presses onto the material along a part of its length, and at least along this section, lies under spring pressure, with its side that is removed from the material to be cut, against a pressure device that extends in the lengthwise direction of the conveyer.
A cutting device of this type is already known, see German DE-OS No. 25 14 836.1. The conveyer element disclosed in this patent consists of a drivable V-belt, the slack side of which, running in the transport direction above the material, is pressed by a spring and a pressure device against the top side of the material which is lying on a lower transport element which, in the pressure area, i.e. the section in which the pressure device presses the V-belt against the material, is supported from below. This lengthwise section extends from a spot located at a distance from the cutting spot of the cutting knife, corresponding to about the length of the material, to a spot behind the cutting spot which is at about the same distance. The pressure device has the shape of an elongated spring-charged plate, extending in the lengthwise direction of the V-belt, of which both short sides are rounded and of which the outer rim is worked along all its sides in such a manner that an endless roller chain can run around the plate. Along the lower lengthwise side of the spring-charged plate, the roller chain presses against the inside upper side of the lower side of the V-belt, so that the lower belt side is pressed, along the pressure section, with its outside lower side against the material to be transported.
When cutting folded or unfolded sheets, as well as booklets, the quality of the cut depends on the material being perfectly clamped in the cutting area. The known cutting device is not fully satisfactory in this respect, because if there are variations in thickness in the piles, booklets or sheets, it is possible that individual sheets, booklets or piles will not be clamped firmly, as required for a clean cut.